the sense that is derived from the game "Call Of Duty Modern Warfare 2" that the sense when you hear a the click of the claymore and you try to run off or jump out of the way but you die. (Also applies in real life such as when you say something uncalled for or inappropriate for the situation and you want to take it back but you cant hence the claymore has already exploded).

Claymore Moment

a: I was going to get that camping piece of shit in the planes cockpit but as I turned the corner and heard the click and tried to go back but it was no use.

b: as I was trying to crack a joke to impress a girl i said a very sexist joke and I wanted to take it back but the claymore has already exploded as in she started to beat the shit out of me with her purse dildo.